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Widespread interest in HVCs is due to their mystery... > Debatted origin Galactic fountain Tidal debris of local group dwarf galaxies Dark matter halos in the Local Group Physical description, spatial distribution, masses and dynamics

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… and their potential for being important > Formation and evolution of galaxies Potential tracers of small dark matter halos Source of gas to fuel star formation Accretion of low metallicity gas for chemical evolution Energy, mass and angular momentum flows within galaxies

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Multivariate regression to estimate the infrared emissivity of each HI component. First detection of dust emission in the HVC –HVC Emissivity at 100 m ~ 10 times smaller than local gas, but only a factor 2 smaller at 160 m Colder dust Infrared-HI correlation I (x,y) = i i N HI i (x,y) + C (x,y)

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Conclusions and Perspectives Confirmation of dust detection result on other fields HVC in Spitzer extra-galactic fields: dedicated GBT+DRAO observations scheduled Dedicated Spitzer observing program? HVCs could make part of the sub-mm extra-galactic background! Search for CO emission from molecular clumps IRAM 30m proposal Clumps origin: self gravitating long lived structures or signatures of the dynamical interaction with the Galactic corona New perspective on HVCs and the Galaxy evolution New hunting grounds for molecules ?